During filling of sacks with a pourable material, for example of a powdery plant-protective material, large amounts of air enter the filling chamber. An air-tight closed sack, however, should not contain too much air, since only sacks from which air has been removed can be stacked. In the case of many pourable goods, the air escapes relatively slowly from the spaces between the particles. Therefore, up to now in many filling operations, the sacks could be closed only after a certain waiting period. To speed up the air removal, pressing mechanisms are also used, which compress the fill material and in this manner speed up the escape of the air. The sack is closed only after the filling chamber has been sufficiently depleted of air. The cycle time of a conventional filling machine is thus usually chosen to be relatively long, in order to make available the necessary air removal time.
A basic purpose of the present invention is to provide a method in which the air removal does not result in an extension of the cycle time of the filling machine. Also, the invention is supposed to provide an apparatus for carrying out the method, and a sack construction which is particularly advantageous in connection with the method.